Wherever rotating shafts are present in machinery and other such equipment it is necessary to support the shafts by means of a bearing in a housing. The bearings typically used are roller bearings or ball bearings, for example. With either type of bearing it is necessary to maintain sufficient lubricant therein to minimize wear of the bearing and the shaft and to prevent seizing of the shaft within the bearing. For this reason a seal is used at the outside edge of the bearing housing to prevent loss of lubricant.
Not uncommonly the seal in the bearing fails. This may be due to a number of reasons but the result is that the lubricant is permitted to escape from the bearing. Unless this problem is corrected in a timely manner the bearing may be ruined, the shaft may become scored, and the remainder of the machine or the equipment supported by the shaft may become damaged.
Conventionally the failed or inoperative seal is removed entirely and replaced with a new seal. However, this procedure requires disassembly of at least a portion of the machine or equipment. Of course, this necessarily involves a great amount of time and expense. When the equipment or machine is very large the repair procedure will also require the use of large and high capacity tools such as hoists, cranes, etc. in order to lift and move certain portions of the machine which must be disassembled before the seal may be removed.
For example, when the equipment which must be repaired is an oil well pumping unit, the shafts are several inches in diameter and the crank arms supported on such shafts are several feet long and weigh hundreds or thousands of pounds. Accordingly, in order to replace failed seals in such a unit the repair process is very time-consuming and is very costly. Furthermore, heavy equipment is required to handle the disassembled components. Moreover, the lost production time can result in a considerable loss until the repairs are completed and the unit is placed back in service. There are many other types of machinery and equipment in use in various types of industries which present similar problems when seals fail.
Although there has been suggested one type of split seal which may be installed around a shaft, use of such seal does not overcome all of the problems normally encountered nor is it suitable for all applications. Such seal is available from Garlock under the tradename "Split Klozure" and is U-shaped in cross-section. A plurality of metal fingers molded into the rubber seal body maintain the desired U-shape. After the seal has been fitted over the shaft a separate cover plate assembly must be made which is then bolted onto the bearing housing to firmly secure the seal in the desired position. This requires that sufficient space be available in front of the face of the bearing housing to enable the use of drills, etc. to form and then thread the requisite holes in the bearing housing. It is also necessary to make a suitable cover plate for each installation.
Of course, there is not always sufficient available space at the seal location to enable holes to be drilled and threaded, for example. Nor is there always sufficient space to accommodate the required cover plate. Moreover, the Garlock seal does not have the capability to accommodate shafts of many different sizes. Rather, only minor variations in shaft sizes can be accommodated by an individual seal.
The present invention provides a seal design and sealing techniques which overcome the disadvantages associated with conventional seals and with the Garlock seals.